A submersible motor-driven pump is often used for fluids removal/ production from wells after operation of perforation and/or formation fracturing. In such cases, rock debris and proppant particles often continue to penetrate the well from the fractured/perforates formation over a certain period of time. Small debris remaining after perforation typically enter the well from the formation over a rather short period of time; however, in case of the formation fracturing, the reverse flow of proppants could last over an extended period ranging from a few days to several weeks from the production start day.
Dependent of the pump position above the peroration site, some solid particles could reach the suction hole of the electrical submersible pump. Thereafter, they will start passing through the pump section carried by fluid. Since the fluid velocity in the pump system is rather high, these particles could cause a significant erosion of impellers and diffusers.
Following the perforation and before the installation of an submersible motor-driven pump pump, the stimulated well is typically subjected to cleaning.
In depleted formation, the lift technology is usually required. In these circumstances, wells can be cleaned through arranging the circulation of a fluid with desired composition via a flexible coil tubing; the said fluid can lift upward the suspended heavy particles. In other cases, a temporary submersible motor-driven pump is installed in the well to ensure hydrocarbons production alongside with the well cleanup (and fracturing). Meanwhile, it is known in advance that the installed temporary submersible motor-driven pump has to be replaced with a new submersible motor-driven pump following a rather short operating period (typically, several weeks).
The above-mentioned well cleanup technologies are expensive and require idling of the well (while the flexible coil tubing is in operation or submersible motor-driven pump is being replaced).
Electric submersible pumps are known to be damaged by small-sized particles in the course of operation. These damages limit the service life of submersible motor-driven pump and the pump should be replaced. The pump replacement procedure is rather expensive and required idling of the well (at least for a period when works in the well are performed).
To handle the problem of declining capacity of submersible motor-driven pump because of erosion by large-sized particles, the suction line of submersible motor-driven pump is sometimes furnished with filters. A typical issue that arises due to the filter operation is clogging after a certain period of operation; the filter clogging results in a reduced throughput or in a fully obstructed flow. So, submersible motor-driven pump and filters has to be removed from well for replacement and maintenance.
A wellbore fluid could contain (dependent on well type and treatment technology applied before the installation of an submersible motor-driven pump) three types of solid particles:                solid particles originating during perforation. These solid particles could be represented by small debris of perforation tools, casing and cement as well as by various-sized rock debris coming from the well walls immediately after perforation (or in first moments of hydrocarbons production following the perforation). In case if some perforation technologies (with a positive pressure drawdown and at a highly depleted formation) are employed, the above-mentioned solid particles can go into the productive flow right from the start of the submersible motor-driven pump operation;        proppant backflow. This issue emerges after the formation fracturing. Some proppant particles could be washed-out from the well at the initial stage of production. Information that at a total backflow of proppant in some wells in West Siberia could account for up to 2 tons (which corresponds to uncompacted 1 m3) is available. The proppant particle shapes could deviate from an ideal spherical shape, and some particles are crushed during the formation fracturing closing. This means that particles with broadly varied sizes could enter the well. The proppant backflow could last several weeks, while the concentration of solid particles, starting with the first day of production, typically reduces to negligible levels;        formation rock solid particles. These particles are rather small and are produced together with the formation fluid. A percent concentration of solid particles in the produced fluid could remain constant over a long period of time. The percentage could attain 200 ppm (which corresponds to a significant volume of a daily flow rate of particles in case of high-yield wells, e.g., those with a daily yield of 5,000 barrels and above). It is a challenging to handle that amount of solid particles.        
A wellbore filter design comprising a casing with circulating passages, filtering element mounted on the casing and designed with stringers with a wire coiling placed on the said string, a supporting ring shroud to rigidly fix the end surface of the filtering element mounted at the casing, and a crossover shoe, is known (RU, patent No. 2102585). Besides, it is furnished with an enclosure that forms a ring chamber with the casing and the crossover shoe, and a sleeve with radial passages and supporting elements placed inside the said ring chamber; some supporting elements of the sleeve are placed in the bushing radial holes, while the remaining supporting elements of the bushing are installed in the slotted openings of the casing; the enclosure and the sleeve are connected by cut-off elements. A sophisticated structural design and a lack of packing between the filter housing and the wellbore walls are the disadvantages of this filter design.
A filter for downhole submersible motor-driven pump comprising a casing with filtering elements and a sealing element (gasket) mounted at the housing to separate the intake and discharge parts of the filter is also known (SU, authorship certificate No. 1660587).
A low strength of the sealing element (distorts during installation procedure and creates leakage) is the obvious shortcoming of this engineering solution.
The most similar analogue to the disclosed design is the strainer for downhole pumps (RU, patent No. 2217580), which includes a housing with filtering elements and a sealing element to put the boundary between the intake and discharge parts of the strainer; the said sealer is designed in the form of a bell filter with a spherical collar mounted on it, with the said sealing element hinged to the filter housing.
The rigid structure of the sealing element creates problems with lowering the strainer to the well and may cause the damage of the said strainer. This damage creates leakage in the top part of the strainer.
The way of resolving the engineering issue is development of a new design of the wellbore filter.